This invention relates to a power control and motion conversion device for a reciprocating heat engine, and more particularly to a Stirling engine power control and motion conversion device for power modulation and conversion of the reciprocating motion of the pistons to rotating motion of an output shaft. This invention is related to the inventions disclosed in Application Ser. No. 242,453 for a "Phase Control for Double-Acting Stirling Machine" and Application Ser. No. 242,452 for "Independently Variable Phase and Stroke Control for a Double Acting Stirling Engine," both filed by David M. Berchowitz concurrently herewith, the disclosures of which are incorporated by reference herein.
The conventional mechanisms for converting between the reciprocating motion of a piston and rotating motion of a shaft developed for internal combustion engines are used primarily because of their reliability. However, there are some disadvantages connected with their use which are inherent in their design. They are heavy and bulky and require a large volume crankcase. Moreover, they exert substantial sideloads on the piston rod.
The power control techniques for Stirling engines that have been developed and adopted to date are usually effective but are often expensive, complicated, and unreliable, and sometimes introduce distinct torque jumps in operation rather than a smooth power transition. They present servicing problems which are well beyond the abilities of the average serviceman and also present manufacturing problems that would introduce severe quality control difficulties in any large scale manufacturing operation.
In order for the Stirling engine to be accepted by industry for wide scale production in applications requiring power modulation of a rotating output shaft, it will be necessary to improve the motion conversion device and provide a power control technique that is suitable for use in the real world.